Erosion in pumps and stationary flow passages from slurry particles is of great importance in equipment for wet mineral and coal beneficiation processes. Since the operating conditions and materials vary and are difficult to monitor in the field, only general guidelines on wear can be expected from operating experience.
The scale of the wear process is of the order of the particle size involved, which typically is 0.1 mm (0.004 inches). Larger particles may be present in the slurry, but their number in contact with the passage walls is small. Local wear on such a scale can be tested in the laboratory and then extrapolated to full-size equipment if the laboratory conditions are closely controlled to provide an absolute value of wear rate and if local flow conditions can be calculated in full-size equipment.
Wear test fixtures of the jet inpingement type and of the paddle wheel type are known and are useful development tools. However, local flow conditions are not precisely controlled and cannot be easily calculated or analyzed in such wear test devices. Further, such test fixtures are unsuitable for testing materials of very high wear resistance because of the excessive testing time required, deterioration of the test equipment and attrition of slurry particles. More important, such test devices do not model the particular wear mechanism encountered in slurry systems.